Improvement in hot-air engines



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AA.K.R1D|R. Improvement in Hot-AirEngines.

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A. K. RBDER.

Improvement in Hot-Air Engines. No.128,979, Patentedsufy 16,1872.

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y 'M4K Swimmer UNITED STATES' ALEXANDER K. RIDER, OF NEW YORK, N. Y.

IMPROVEMENT IN HOT-IR ENGINES..

Specification forming part of Letters Patent No. 128,979, dated July 16,1872.

l character, I will call attention to the features which involvenovelty. v

The accompanying drawing forms a part of this specification.

Figure lis a central vertical section of so much of a'complete engine asis requirednto show the novelty and to indicate the relation -of thenovel parts to the other parts. Fig. 2

is a view of a small portion at right angles to the view in Fig. 1, andFig. 3 is a section, showing a detail on a large scale.

Similar letters of reference denote corresponding parts in all thefigures.

Denoting the working-cylinder by A, the bottom--usuallytermedtheheater-by A', and the supply-cylinder by B, I introduce anintermediate casting or waist-piece, marked G,which performs the severalfunctions of rmly connecting the parts, conveying the air from thesupply-cylinder to the working-cylinder, distributin g it uniformlyaround to enter the narrow space provided for its admission into thebottom of the heater, and thus into the space below the working-piston,and serving to cut off or arrest the conduction of heat upward from theheater to the rubbing surfaces. The supply-piston, marked b, is jointedto a rod, b. The working-piston a is jointed to a rod, a. Both areconnected to cranks on a single shaft mounted directly above. The shaftis marked D, and the cranks E and G. These cranks -stand not at rightangles, but forming an angle of seventy degrees with each other. Themotion is in the direction of the arrow in Fig. 2, the workin g-crankbeing ahead of the other. The valves 'm a in the base of thesupply-cylinder B are self-acting. The air is inducted through the valvem on the ascent of the supply-piston b, and is discharged through thevalve n during the descent thereof'. y His the exhaust-passage, which,it will be understood,

is controlled by a valve, h, of ordinary construction, represented indotted lines. This valve is operated by a cam or analogous dcvicethrough suitable connections.

Operation.

When the working piston a has ascended nearly to its highest elevationthe exhaustvalve h opens, and the piston, on descending again, meets noresistance until it has arrived near its lowest position, when theexhaustvalve h closes. In the meantime the supplypiston b has completedits up stroke, thereby flllin g the supply-cylinder B with cold air, andhas commenced to descend and force the same through the delivery-valvea, and through the passage in the waist-castin g C into the bottom ofthe working-cylinder. This action has an important influence on thesuccess of my machine; for, as the cold air thus driven through thepassages requires au appreciable time to raise its temperature, it, bybeing delivered thus uniformly at a low temperature all around theworking-cylinder, drives before it the hot air with which the. spaceswere previously filled; and, at the moment of the closing of theexhaust-valve h, there is an act-ive current of air outward through theexhaust-passage, due to the fact that the descending motion of thesupply-pistou b has progressed one-fifth of its stroke downward, andthat the cold air is being driven thereby into the working-cylinder.- Onthe closing of the exhaust-valve h the continued descent, both of theworkingpiston aand of the supply-piston b, compresses the air under bothto a nearly equal extent. It follows that there is for a little periodno motion ofthe air through the interior of thewaistpiece C, but simplyan increase of density and pressure. This condition obtains until theworkingpiston a commences to rise. This motion,be ing followedup by theabout equal descent of the supply-piston, causes a rapid and completetransfer of all the cold and compressed air into the heater withoutmaterial change of volume. The result is immediate augmentation ofpressure, and afterward, as the working piston moves upward, increase ofbulk or volume. Thus the greatest possible result is attained in theamount of power developed. This transfer is accomplished without anyconsiderable change of volume. It is a transference of the e i 12emecompressed air, in its compressed condition, from thecompressing-cylinderB into the base of the working cylinder A. Thatportion which has not yet entered into the working cylinder remains inthe waist-piece C, which is carefully devised to present a smallcapacity, and as the working piston a afterward rises the air followsit,passing by successive increments from the limited reservoir in thewaistpiece C under the curtain x, which is an extension downward of theworking cylinder A, and thence up into the base of the working cylinderproper, becoming heated and expanded in the operation.

I attach much importance to the ratio of the entire clearance space tothe amount of air.

compressed by the working piston in its descent. The volume of airarrested by the early closing of the exhaust-valve being compressed inthe base of the main cylinder A and the connected passage, reaches atension fully equal to that in the supply-cylinder, in` order that thecold air compressed by the descent of the supply-piston shall remainwhere compressed until the proper time for its transference into theheater.

If the air is allowed to pass into the heater during its compression ittakes more power to compress it. I avoid this loss of effect bycompressing just sufficient of the previously hot air to keep the coolback until the compression is nearly or quite complete.

The regulation is effected by a fly-ball or other ordinary governor, notrepresented, acting upon a tube, J, placed between cup-leather packings,7a k', in a casing, K, which communicates with the interior of thewaist-piece C.

When the work requires all the power of the engine the tube Jv standslow and discharges no air. As the speed increases the tube J is drawnupward, and when much too great it allows a large quantity of air toescape through minute perforations arranged aroundthe lower portion ofthe tube J. These apertures should be small, and the exterior ofthe tubeJ at that point made smooth, so that it will run freely past thecup-leather 7c. This regulator-valve, as I will term it, works withoutappreciable friction, and may be of such size as to control the speedvery efciently under all ordinary conditions. I can effect the sameobject, to some extent, by a throttle-valve in the passage C connectingthe supply and main cylinders;

` said valve bcing, of course, attached to the governor. But I prefer.the plan first described. The shaft D may be mounted below and connectedby beams or links,the angles of the cranks' being preserved 5 but Iprefer the direct connection, as shown. The cards or diagrams on sheet Qwill be understood with a brief explanation. The uppermost shows twocards superposed one upon the other. ,The strong line is the pump-card,and shows the power consumed in the action to keep the air suppliedproperlyby the pump. The extremity at and near the right is blank, orthe pencil returns on the same line as it goes out, because theexhaust-valve h is wide open. The heavy dotted line is theworking-cylinder card. The effective power of the engine is the arearemaining after the pump card is deducted from the other.

The fine series of dots shows the card of an engine of equal capacity onthe ordinary plan, or, more specifically, on the plan which I esteem thebest next to this, and which is set forth in the patents issued to me,dated October 24:, 1871, No. 120,325. The card near the bottom of thesheet is a merely theoretical diagram, illustrating the effective actionafter the work due to the resistance of the pump has been deducted.

Some of the advantages due to certain features of my invention may beseparately enumerated as follows: First, by reason of the fact that thesupplycrank or pump-crank Gr is mounted behind the other, and that theexhaust-valve his held open until the supplypiston b has descended aboutone-fifth of its stroke, I am able to rinse out, so to speak, the entireclearance-cavity,l and to fill it with cold air. The gain due to this isexperienced inthe superior facility with which the air may be afterwardcompressed to a given density by the further descent of the two pistons.Second, by reason of my waist-piece C, constructed and arranged asrepresented, I am able to connect the parts strongly and firmly, withgreat facilit@ for removing and exchanging the heaters A', and todistribute the air evenly and efficiently around the base of theworking-cylin-- der, while contributing greatly to arrest the conductionof heat from the heater to the working cylinder. Third, by reason of theclosing of the exhaust-valve h before the descent of working-piston a iscompleted, and after the commencement of the descent of the supplypistonhas driven out most of the hot air, I am able to compress the air in thebase of the working cylinder to a tension fully equal to that induced inthe supply-cylinder, and preferably a little in excess thereof, and tothus hold back the supply of air and prevent its becoming heated whileundergoing compression. Fourth, by reason of my attaching the 4 thatthere would not be sufficient dierence in time to induce an effectualtransfer of the air. They would be too nearly on the center at the sametime. On the other hand, at ninety degrees, while a very considerabledifference of time, or, as it may, perhaps, be better termed,

range of transferring space, could be secured, the requisite degree ofcompression could not be got before the main piston moved away. Theblowing through of the air contained in, say, one-fifth of the capacityof the pump and the closing of the exhaust-valve in the proper time tomeet the requisite condition of compression calls for about seventydegrees of the cranks with ordinary length. Fifth, by reason of thetubular perforated valve J, connected to the regulator and workin gwithin cupleathers k k or equivalent delicate self-adjusting packings, lam able to offer a large area for the discharge of air with a slightmotion of the governor and with little resistance to motion or friction,thus securin g great delicacy and efficiency of action.

I claim as my invention and desire to secure by Letters Patent- 1. Thesupply-crank G, operated behind the working-crank E, in combination withthe closing of the exhaust-valve h after the`workingpiston b hascommenced to descend, as herein specied.

2. The waist-piece G, in combination with the parts A A and B,constructed and ar-A ranged as represented, for the purposes set forth.

3. The construction and mode of operation specified, whereby the closingof the exhaustvalve h induces a compression in the clearance space equalto the simultaneous compression in the supply-cylinder.

4. The tubular valve J, constructed and arranged relatively to thepackings k k and casing K, substantially as and for the purposes hereinspecified.

In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnes'ses.

' A. K. RIDER.

Witnesses THoMAs D. SfrETsoN, ARNOLD HOERMANN.

